Portable electric measuring instrument.



' PATENTBD APR.16, 1907.4

No. 850.1129. f

. mouksols. PoRTABLE BLEU TRIG MEASURING INSTUMENT. ArPLIoATIon FILED JULY a1, ums.l A

lll/I.

HENRI BOURGEOIS, OF DAMPRICHARD, FRANCE.

PORTABLE ELECTRIC IVIEASURING INSTRUMENT.

Specification of Letters Patent.

rammed April 1s, 1907.

Application iiled July 31,1905. Serial No. 271,941.

T0 all whom, it 11i/ty concer-71,.'

Be it known that I, HENRI BOURGEOIS, of Damprichard, Department of Doubs, France, have invented a new and useful Improvement in Portable Electrical Measuring Instruments; and I do hereby declare the following to be a full, clear, and exact description of the same.

One embodiment of this invention is shown, by way of example, in the annexed drawings.

Figure 1 is a plan of the side opposite the dial of the instrument,'the bottom of the casing of which is removed. Fig. 2 is a section along the line A B of Fig. 1. Fig. 3 is a side elevation of the pendant of this instrument, the bow being reversed to disengage the contact-point of this endant.

The instrument, whic may be a volt or ampere meter, according to the winding of the solenoid and the division of the dial,

lcomprises a metallic case a, similar to the cases of watches, and in which is adjusted a plate l), of insulation material -such, for example, as ebonite-on which 1s xed by the screws c a metallic plate d, supporting a spring-barrel e, around which 1s rolled an insulated flexible conducting-wire f, which the spring of the barrel tends to keep constantly wound. One extremity of the conductor f is in metallic contact with the drum c, and lconsequently the plate d, while the other extremity passes through the case a to the insulating-cannon g and is lixed to a metallic rod carried by an insulating-button t. This rod h is frictionally held in the button i, and it terminates at one extremity in a point, while the other end is flattened out in such manner as to be able to be seized by a pair of pliers. vThe bare end j of the conducting-wire f is engaged in a transversal hole of the rod h, and on turning this rod by means of a pair of pliers there is wound on it in the interior of the button i not only the bare part of the wire but also a part of the same covered with its insulation, so that while doing away with solder a very secure junction is formed between the wire f and the button h contrary to what was done generally in other similar instruments where all the strain is supported solely by the bared part of the conducting wire, which frequently breaks.

The solenoid is formed of a bobbin of copper k, around which is wound the insulated wire Z, connected at one part to the plate d and on the other to a metallic rod m, passing through an insulating-cannon n, placed in the interior of the pendant o, soldered to the case a. The rod m is fixed to the pendant by a nut p, and it terminates toward the top in a point, which when the instrument is not in use is hidden by a screw g, screwed into the middle of the bow r, this screw terminating in a milled button s, enabling the same to be screwed by hand on the point of m, as represented in Fig. 1, when the instrument is not in use or to be unscrewed in order to incline the bow o and disengage the contactpoint in order to take a measurement, Fig. 3.

The bobbin 7 of the solenoid is freely adjusted in a circular groove t of the insulatingplate b, and it is held on this plate and in this groove by the head of two screws u, screwed into the said plate t. The interior wall v of the bobbin of the solenoid carries the softiron pin zr, acting on the iron plate y of the needle z. The whole of the solenoid is concentric with the support 1, between which and the center of the yoke 2 the needle z is pivoted, and the needle is independent of this support, so that it is possible by disengaging the screws u u to cause the solenoid to turn to bring the pin a: to the desired point or to remove the solenoid and its iron pin completely without removing the needle 2 or its support 1. As a result of the above the whole mechanical and electrical arrangement of the instrument is electrically insulated from its casing, so that no current traverses the former when a measurement is being taken. Otherwise the instrument is used without preparation and loss of time, as it is only necessary to impart a turn or two to the screw q of the bow to cause the same to rock, Fig. 3, and to put in contact with one of the poles, of the source of electricity of which one wishes, for example, to know the potential, the point of the rod m. Then to draw the button i till the conductor f is unrolled for a sufficient length, so that the point of the rod h can reach the other pole of the said source of electricity and be put in contact with it. When one has been able to read on the dial of the instrument the indication of the needle z, one ceases to act on the button i, and under the action of the spring of the barrel e the conductor f is rolled into the interior of the instrument. The bow 1" is then placed in its irst position, Fig. l, and the screw g is made to engage the point m, so as not to cut the pockets of the garment in which the instru- IOO IIO

ment is carried. Lastly, another very great advantage of thlslinstrument resides in the simplelp'regulation ofthe solenoid carrying the soft-iron pin and in the easy dismounting of this solenoid. Without touching the needle or its support.

AThe dial of the instrument, which is not represented otherwise in the drawings, the division of the same, and the dimensions of the various parts of this instrument are capable of variation.

'Having now particularly described and ascertained the nature of my said invention and in What manner the same is to be performed, I declare that What I claim is 1. A portable electrical measuring instrument comprising an outer casing, a plate of insulating material secured Within the same, means to indicate electrical measurements carried by said plate, a solenoid' adapted to actuate said indicating means, one end of the Wire formingsaid solenoid being connected with a pin extending Without the said casing and means adapted to normally cover and conceal the exposed end of said pin, the other end of said Wire being in electrical communication With a s ring-actuated drum, a flexible, insulated, e ectrical conductor extending Without said casing and Wound around and in electrical communication with said drum, and means secured to the outer end of said electrical conductor to prevent the latter being drawn Wholly Within said drum, the parts being so arranged that said electrical conductor may be partially drawn Without said casing against the tension of the spring adapted to actuate said drum and automatically rcwound upon said drum by said spring When the said conductor is released.

2. A portable electrical measuring instrument comprising a casing, means Secured therein for indicating electrical measurements, means to actuate said measurementindicating means, contact-pins connected by current-conducting Wires with said actuating means, one of said contact-pinsbeing movable, a head secured about portions of said last-named pin, and a portion of the currentconducting Wire connected With said lastnamed pin being normally Wound around a spring-actuated drum adapted to exert tension upon said Wire tending to draw the same Wholly Within the drum.

3. A portable electrical measuring instrument comprising an outer casing, means secured thereinfor indicating electrical Ineasurements, means to actuate said measurementindicating means, contact-pins connected by current-conducting Wires With said actuating means, one ofsaid pins being located Within a stem secured to said casing, a ring .pivotally secured to said stem, and means adjustably carried by said ring for normally covering the outer portion of said pin, substantially as described.

In Witness whereof I have hereunto set my hand in the presence of tWo Witnesses.

HENRI BOURGEOIS. 

